Granulated product and process for making same



Patented Apr. 22, 1930 UNITED STATES PATENT oFFica HENRY C. GARDINER, OF ANAGONDA, MONTANA GRANU'LATED PRODUCT AND PROCESS FOR MAKING SAME No Drawing.

up such arsenical materials as flue dust, bag- 4 house dust, chamber dust, dust produced from the well known Cottrell installation, hot and cold treater dust and all similar materials or products which result from the mettallurgical reduction of arsenic bearing ores and materials.

Another object of the invention is the provision of a process for producing aggregates of fine particles resulting from the metallurgical reduction of arsenic bearing ores so that I the product may be handled more expeditiously and with the elimination of dust.

A further object of the invention is the provision of a process for granulating fine particles of dust resulting from the metallurgical reduction of arsenic bearing ores while at the same time controlling the solubility of the granules thus formed.

A still further object of the invention is the provision of a process for granulating fine particles of dust resulting from the metallurgical reduction of arsenic bearing ores while'increasing the weight per unit volume of the dust thus simplifying and reducing the 1 cost of packing.

This invention will be best understood from a consideration of the following detailed description; nevertheless it is to be understood that the invention is not confined to the dis closure, being susceptible of such changes and m'odifications'which shall define no material departure from the salient features of the invention as expressed in. the appended claims.

In carrying out myinvention, I mix sul phuric acld and water with one or more of the following products,finely divided particles of flue dust, bag house dust, chamber dust, dust produced from the well known Cottrell installation,hotandcold treater dust,

. and all similar materials or products which result from the metallurgical reduction of arsenic bearin ores and materials. The mixing is accomp ed easily and economically Application filed August 22, 1927. Serial No. 214,791.

in an apparatus such as a pug mill or a granulator. Any type of mill suitable for the purpose may be employed. The dusts are first tested in order to determine the percentage of arsenical products. Depending upon the purpose for which the product is adapted to be used, a dust may be mixed with a different kind of dust mentioned above for the pur pose of increasing the percentage of the arsenical products or for decreasing the percentage.

The quantity of the sulphuric acid used is'governcd by the degree of firmness, relative solubility of the toxic components and the quantity of free sulphuric acid desired in the finished product. From one to twenty percent by weight of sulphuric acid may be added. These percentage limits will give a sufiiciently Wide range of degrees of firmness, free sulphuric acid and solubility of the toxic components in the product that such product may be very eificaciously utilized in the preservation of Wood or articles formed of wood which are ordinarily buried or partially buried in the ground and whichare subj ect'to the attacks of fungi, bacteria and insects.

The quantity of water added is dependent upon the type of equipment employed for the purpose ofgranulation. Ordinarily it is only necessary to add suificient water to produce a granulated product in which the granules are of the desired size whereby they will not adhere either to each other or to the granulating and drying equipment. It has been found that as low. as five percent of water by weight will be sufficient to accomplish the desired result. The percentage limits of water are approximately from five to twenty per cent.

The mixing of the sulphuric acid and water in the proper percentages with one or a mix,- ture of two or more of the products resulting from the metallurgical reduction of arsenic bearing ores and materials'may be easily accomplished in a manner that the process will be continuous. The sulphuric acid may be added first and then the water may be supplied in the proper proportion or vice versa. If desired the sulphuric acid and Water may be carefully mixed and this mixture may be drying the mixture.

added directly to the arsenic containing material either in the pug mill or granulator or before the materials have been placed in the apparatus.

The mixing of the sulphuric acid and water with one or a mixture of two or more of the arsenic containing products is done for the particular purpose of providing wet granules of the desired size. is then dried in any type of apparatus suitable for the purpose. A drier of the type commonly known as a rotary dryer or rotary kiln has been found to be most suitable for such a purpose, since the rotary motion produces granules of very firm texture.

While I have stated that sulphuric acid and water are employed within certain ranges of percentages it will be appreciated that other solutions, simple, collodial or denatured, may be employed for the purpose.

Solutions containing starch or sugar, or glues, and flour may be used for the purpose. One such sugar containing substance found to work very effectively is, refuse or stock molasses. After the dust has been thoroughly mixed with the sulphuric acid water it is then dried in any suitable manner, as by means of the usual drying equipment.

I claim 1. A process for granulating dust resulting from the metallurgical reduction of arsenic bearing ores and material which comprises mixing said dust with sulphuric acid and water, agitating and at the same time a 2. A process for granulatin dust resulting from the metallurgical re uction of arsenicbearing ores and material which comprises mixing said dust with sulphuric acid and then water, agitating and at the same, time drying the mixture.

3. A process for granulatin dustresulting from the metallurgical re uction of arsenic bearing ores and material which comprises "mixing said dust with from one to twenty percent by weight of sulphuric acid and from five totwenty percent by weight of water, agitating and at the same time drying the mixture.

4. A process for granulating dust result-J ing from the metallurgical reduction of ar- The mixture dried mixture of a dust resulting from the metallurgical reduction of arsenic bearing ores, sulphuric acid and water.

7. A product of the class described comprising pellets formed'of a mixture of an aqueous solution of sulphuric acid and a dust resulting from the metallurgical reduction of arsenic bearing ores.

8. A product of the class described comprising pellets formed of a mixture of arsenic bearing materials, sulphuric acid and water, said acid acting as a binder for the arsenic bearing material.

9. A product of the class described comprising pellets formed of arsenic bearing materials and sulphuric acid, the acid acting as a binder for the arsenic bearing material.

10. A process of manufacturing a wood sulphuric acid and water, and drying the mixture with agitation to form granules while varying the solubility in water of the toxic components of the dust.

HENRY C. GARDINER. 

